The Major Lunar Standstill, as the cycle is called, has been followed by serious starwatchers since the Babylonians. Like clockwork every 18.6 years, it triggers severe tide spikes, swells, and floods, especially in the tropics. Now, the charts showed that the Standstill was messing with Jakarta. Around Nov. 26 or 27, just a few months away, Brinkman told Abidin and Andreas, Jakarta appeared all but certain to experience a devastating new flood — a surge that would send a half foot of seawater or more over the wall and into the city.

The Radical Plan to Save the Fastest Sinking City in the World

Wikipedia has a Lunar Standstill article but it does not mention tides, and I cannot find (good quality) pages that make this connection .

Can a "Major Lunar Standstill" cause one-day high tides as described in the Jakarta article?


1 Answer 1


Can a "Major Lunar Standstill" cause one-day high tides as described in the Jakarta article?

Possibly "fake news", but very possibly yes.

The possibly "fake news" part first: The next major lunar standstill will be in late 2024 / early 2025. The most recent minor lunar standstill was in 2015. There is no lunar standstill, major or minor, in 2020.

Now for the possibly yes part. The Moon and the Sun excite tides in the Earth's oceans at a variety of frequencies. The dominant frequency in most places is the M2 tidal component with a frequency of 12 hours and 25.2 minutes. This is due to the Moon, whose tidal influence is over twice that of the Sun. There are many other components to the tides. The longest modeled term, the lunar nodal tidal cycle, has a period of 18.61 years.

Each of those exciting frequencies results in a set of amphidromic systems. (Note: The linked site discusses the response to the M2 tidal component. Every tidal component results in its own set of amphidromic systems.) The 18.61 year period lunar nodal tidal cycle results in rather weak tides in general, typically less than a centimeter.

That said, the very long frequency means that this generally small tide can add insult to injury when shorter frequency tides line up to create very high spring tides. Moreover, the shape of continents and the depths of the oceans can make what are normally small tidal influences have locally magnified significance. Miami, for example, experiences annual king tides that flood low-lying parts of the city.

More to the point, many places along the UK coastline experienced the highest tide for 18.6 years between the 19th and 30th of September. Even more to the point, tide gauge records have shown that the 18.61 year period lunar nodal tidal cycle can change high water levels by up to 30 cm.

What about the fact that there is no lunar standstill in 2020? There are a few places experience the M2 appears to be exactly in sync with the Moon in that high tide happens when the Moon is at zenith / underfoot, low tide when the Moon is at the horizon. But it's the other way around in other places: High tide happens when the Moon is at the horizon. In yet other places, high tide happens when the Moon is halfway up in the sky.

The amphidromic systems that result from tidal forcings result in rotating waves about amphidromic points. Places do not in general experience high tide when the Moon is at zenith. Every place instead experiences a phase shift from when one would naively expect high tide to occur. With the 18.613 year lunar nodal tidal cycle, that phase shift could be as much as ±9.31 years. A peak lunar nodal tidal four years before a major lunar standstill is well within the realm of the possible.


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